Spark-plug.



w, H. PLUVNKETT.

SPARK PLUG.' APPLICATION FLLED AUG. 3.1i 1918.

` Patented Jan.14,1919.

-ATENT onrIoE.

WILLIAM H. PLUNKETT, OF RICHMOND HILL, NEW YORK, ASSIGNOR TlOBERNICE B.

PLUNKETT, OF RICHMOND HILL. NEW YORK.`

nannies.

Specification of Letters Patent. Igltenfed Jan*` 14, 1915),

Application filed August 31, 1918. Serial No. 252.164.

To all Ic/lcm t may concern.'

Be it known that 4I,- VILLIAM H. PLUN- nnrr, a citizen ofthe United States, residing at Richmond Hill, in the county of Queens and State of New York, have invented certain new and useful Im` roveinentsin Sparkllugs, of which the iiillowing is a full, clear, and4 exact description.

This invention relates to spark plugs, and has for its general object the provision of a device which combines `the functions of an energizer and-a spark plug. A i

As is well known, an energizer is a device for introduci r a spark gap into an ignition circuit at a point other than the sparking contacts for the purpose of increasing the y tor preventingj` at the sparking contacts,

size oiz the spark and also short circuits either due to an accumulation of carbon, or short circuits through i the porcelain insulator. These euergizrers have been usually placedA at a point adjacent to the spark plug and it is the primary purpose of'this invention to combine the energizin function with the spark plug, so that an integral device is obtained which will haveboth functions.

lt is also the object of the invention to provide a device or spark plug of thischaracter, which is of simple construction, which may be readily assembled, and' which when assembled may be placed in th'e cylinder of the internal combustion engine in the same way as any of the usual types of spark plugs at present used.

A further object of the invention is to provide anv insulator which` combines with the sparking contacts to prevent anyaccumulation of dirt or carbon at the contacts,

4 which might cause a fouling of theplug.y

Other objects of the invention w1ll be apparent from the detailed description hereinafter to follow, when taken in conjunction with the accompanying drawing, and will be particularly pointed out in the appended claims. l

1n the drawing, Figure l shows a View,

partially in section, ,of one type of spark, plug constructedv in accordance with the` principles of the invention; and j Fig. 2 is a bottom plan thereof. The outside shell or bushing 1 of the spark plug, which is of metal, as 1s the usual practice, is.provided with a reduced end 2,

which isthreaded for the purpose of secur' ing the plug in place within the cylinder `a layerl of mica,

upper section 5 "of the insulator is head.` This shell or bushing carries one of the sparklng contacts, whlch 1s designated 3, which, in theform shown, consists of a l an insulator which, in the form shown, comprises three sections designated 5, 6 and 7. The lowermost section il' disposed electrode 8, whiih has a projecting lower end in alinement with the end 4 of the carries` a,` centrally other electrode or contact. This section 7 of the insulator is provided with a beveled "iortion 9, which is sepan pcd from a similar eveled portion 10 of the shell or bushing 1 by a copper asbestos cushion or seat 11.' i The lowermost end of the section 7 is of reduced diameter, and surrounding the projecting end of the electrode is a cup-shaped depression 12. The ends of the electrodes 8 and 3 are disposed Within this cavity or depression. The reduced end portion of the section 7 is also provided with fins 13 which serve to dissipate or radiate the heat andthus prevent excessive heating of the electrode. kThe uprper end `of thesection 7 of the insulator .is

provided with a centrally ydisposedboss 14: and the endl of the electrode 8 also projects beyond this boss. ,Mounted above the section Tis the intermediate section 6,' which is preferably separated from the lower section by or other insulation. This section also carries a centrally disposed elec trode 17` which is embedded therein in the usual manner.` The section 6 is also provided with a centrally disposed cylindrical openprovide a chamber-,a in which are positioned the alin-ing ends Vof the electrodes 8 andl?.

These ends areipreferably somewhat pointed i to decrease the resistance of the spark gap,

whichis formed between them. The inter- ,mediatey section 6 is also provided-with a centrally `disposedcylindrical boss 19L- The i l also provided with a Vcentrally disposed cylindrical cavity, the lower end-of which fits over the boss 19 to provide a second chamber b simi lar to the chamber' 'a. The section 5 carries `an electrode 20 having` its end projecting into the chamber?)` in' alinement with the ing or cavity, the lower endof which fits circuit (not shown) to the spark plug.

The section 5 of the insulator is provided with a shoulder 23, and a gasket .24 which is threaded into the open upper end ot' the shell or'bushing l is screwed down upon the shoulderto firmly clamp the three sections of the insulator within the shell or bushing.

This gasketis provided with .a hexagonal flange 25 `for screwing it into position and is preferably separated from the shoulder 23 by a copper asbestos cushion.

, The method of assembling the plug is obvious from its coi'istruction, the sections 7 and 6 being first placed within the shell and finally the Section5, which is then clamped in position by the' gasket 2l. T he layers 16 and 19"-whicli separate the sections of the insulator also serve as spacers to determine the length of spark ga formed by the electrodes within the chain ers a and 7). tor since the 4electrodes are rigidly secured in the insulators it is evident that the thickness otV the layers of insulation will determine the length of the spark gap.

In use the three spark gaps must be simultaiieously arced in order to close the circuit, which will cause a higher potential to he accumulated than it only one spark gap is utilized. The result of this is that a spark 'ot' greater size is produced at the electrodes 3 and 12, which will he ot'greater sharpness and brilliancy, due tothe high potential which is caused'by the plurality ot' spark gaps. In practice, it has heen found that. the size and strengthof the spark at the sparking contacts is sufiicieiit to. keep the sparking contacts clean at all times without any danger-Otl fouling. |The sparking contacts are preferably arranged as shown, that.. is, positioned within the cup-shaped depression in the end of the insulator, which will prevent the accumulation .of oil upon the sparking contacts, since thiy cup serves as a refiector for the spark.

In other Woi'ds, since the spark is fired within the cup the flame from the spark will, when it strikes the walls ot the cup. he defiected or reflected outwardly, which will tend to carry with it any accumulation of oil vwhich may gather adjacent to the sparking contacts and will therefore maintain these contacts clean.

Heatingof the electrode is also prevented -hy the heat-dissipating or radiating fins 13.

While aplurality of spark gaps are shown of value, although it is believed that it would not be as efficient as the plurality of spark gaps shown. It is intended, however, that sucha construction will come within the Vpurview of this invention as set forth in the appended claims.

I claim:

1. In a spark plug for internal combustion engines, a plurality of insulator sections. an electrode in each section and a separator between adjacent sections to control the size of the spark gap between the ends of the electrodes.

Q. In a spark plug for inte Vl combustion engines'a metallic shell` W insulator sections in said shell/anelectrode carried by each insulator section, the ends of adjacent electrodes being placed to provide a spark gap and a separator between two adjacentinsiilator sections to control the size of the spark gap,

3. In a spark plug for internal combustion engines.` a metallic shell. a sectional insulator mounted in said shell each section having an electrode passing axially therethrough, saidsections arranged in abutting lrelation, the ends of said electrodes being lurality of tion engines. a metallic shell, an insulator comprising a plurality of abutting sections mounted within said shell` said sections having a plug and socket connection. said sockets being of grcatcr'deptli than said plugs to provide cavities, means for clamplng the sections of the insulator together and to the shell. an electrode section in each section of said insulator. said electrode sections having their ends spaced apart' and located within the cavities formed within the insulator.

In witness whereof, II subscribe my signature.

WILLIAM H. PLUNKETTM` 

